CORNEAL DYSTROPHIES PRESENTATION IN OPTOMETRIST PERSPECTIVE

 DEFINITION
 DIFFERENCES BETWEEN DEGENERATIONS AND
DYSTROPHIES
 CLASSIFICATION
 EPITHELIAL DYSTROPIES
 STROMAL DYSTROPHIES
 ENDOTHELIAL DYSTROPHIES
 SUMMARY:
 REDUCED CORNEAL SENSATION
 RECURRENT CORNEAL EROSION

 Bilateral,
 Symmetric,
 Non-inflammatory,
 Opacifying ,
 Inherited or genetically determined condition with
 little or no relationship to environmental or systemic factors.
 Most corneal dystrophies have an onset prior to age 20 years
(exceptions include map-dot-fingerprint dystrophy and Fuchs
corneal dystrophy)
 Most corneal dystrophies are dominantly inherited, exceptions
being macular dystrophy, type-3 lattice dystrophy, and the
autosomal recessive form of congenital hereditary endothelial
dystrophy

Features Degeneration Dystrophy
Onset Presents later in life,
associated with aging
Present early in life,
hereditary
Laterality Unilateral Bilateral;
May be asymmetric
Bilateral & symmetric
Family history Uncommon Common
Vascularization Common Uncommon
Location often peripherally
located
Centrally located
Progression Progression can be very
slow or rapid
Progression usually slow

 Classified according to
 genetic pattern,
 severity,
 histopathological features,
 biochemical characteristics or
 anatomical location.
 IC3D(International Committee for the Classification
of Corneal Dystrophies) established in 2005 has
revised the dystrophy nomenclature.

EPITHELIAL
 EBMD
 MEESMAN’S DYSTROPHY
 LISCH
BOWMAN’S LAYER
 REIS BUCKLER
 THIEL BEHNKE
STROMAL
 GRANULAR
 AVELLINO
 MACULAR
 LATTICE
 SCHNYDERS CRYSTALLINE
DYSTROPHY
 GELATINOUS DROP LIKE
 FLECK’S CORNEAL
DYSTROPHY
 CENTRAL CLOUDY
DYSTROPHY OF FRANCOIS
ENDOTHELIAL
 FUCH’S ENDOTHELIAL
DYSTROPHY
 POSTERIOR
POLYMORPHOUS
DYSTROPHY
 CONGENITAL
HEREDITARY
ENDOTHELIAL
DYSTROPHY (CHED)

 Also known as map-dot fingerprint
or Cogan microcystic dystrophy
 Usually sporadic, may be AD
 Most common dystrophy
 Bilateral, more common in women
with increasing frequency over the
age of 50.
 Onset in the 2nd decade

 EBMD is an abnormality of epithelial turnover, maturation, and
production of basement membrane.
 Thickened basement membrane with deposition of fibrillar
material between the basement membrane and Bowman’s
membrane.
 Damaged sub-basal nerves causes reduced corneal sensation.
 Epithelial microcysts with absent or abnormal
hemidesmosomes
 10% develop recurrent epithelial erosions

Symptoms:
 Due to recurrent
epithelial erosions
 Pain on awakening
 Blurred vision
 Monocular diplopia
 Image ghosting

 Management:
• 5% NaCl drops or ointment
• Lubricating drops/ointment
• Epithelial debridement
• Patching
• BCL
• Phototherapeutic keratectomy
• Stromal puncture in recalcitrant cases using a 20-25G
needle(0.1 mm depth)- anterior micropuncture
 Superficial keratectomy
diamond burr
PTK
excimer laser ablation
EBMD increases risk of failure of LASIK

 Very rare epithelial dystrophy
 AD with gene locus on 12q13 or 17q12: mutation in Corneal
Keratin K3 and K12.
 Patients asymptomatic till 4th-5th decade
 Cornea may be thinned and sensation reduced
 Symptoms
may be asymptomatic or symptomatic in first few years of
life
-mild irritation & Decrease of vision.
-pain, redness, photophobia because of
recurrent erosions due to rupture of cysts

 Epithelial microcysts consisting of
epithelial cell debris concentrated
centrally
 Intracellular “peculiar substance”
 Clusters of tiny round cysts in the
epithelium
 extending out to the limbus
 Most numerous in interpalpebral area
 coalescence of cysts may form refractile
lines
 Cornea may be slightly thinned and
corneal sensation reduced.

 Management:
Mostly no treatment required
- Lubrication
- soft contact lens
- superficial PTK, rarely

 AD or X-linked on Xp22.3
 Gray band shaped & feathery lesions
of densely crowded clear microcysts
appear in a whorled patterns.
 Symptoms:
 possible decreased VA,
 no pain
 Treatment: Usually none,
but sometimes corneal
debridement or RGP contact lenses

 Autosomal dominant (keratoepithelin gene on
chromosome 5q31)
 Manifests in first decade of life
 Superficial gray white linear, geographic, ringlike
opacities at the level of Bowman’s layer comprising
of fibrous tissue.
 Symptoms –
 Onset in first 1-2 years of life
 Pain, redness, photophobia, decreased vision due to
severe recurrent corneal erosions.
 Corneal sensation is reduced.

 Histology- Bowman’s layer is
completely replaced by masses of
disoriented collagen fibrils and
smaller electron dense fibrils
 Leads to a reticular pattern in an
undulating, “sawtooth”
fashion, corresponding to
subepithelial opacities

 Treatment
 Symptomatic for corneal erosions
Superficial keratectomy
Lamellar keratoplasty
PTK
Rarely PK
 Recurrence in the graft is common

 The excimer laser utilises 193 nm ultraviolet light to disrupt
intermolecular bonds in the cornea by a process termed
"photoablative decomposition“
 PTK allows the removal of superficial corneal opacities and
surface irregularities.
 After adequate excision of scar tissue, the irregular corneal
surface masked using 2% methylcellulose to produce a more
uniform surface profile. Laser ablation performed using an
appropriately sized beam.

 AD
 Chromosome 10q24 and 5q31
(keratoepithelin gene)
 Same pathogenesis and clinical
appearance as Reis-Bucklers
dystrophy but with a more
honeycomb pattern, “curly
fibers” sub-epithelial fibrosis
 Treatment: same

 Very common
 AD
 Pathogenesis:
 Amyloid deposits concentrated in anterior stroma and
subepithelial areas poor epithelial-stromal adhesions
leading to recurrent corneal erosions
 Stains orange-red with Congo Red dye and exhibits
characteristic green birefringence when viewed through
polarizing filter. Also stains with Massons trichrome and PAS.

 Central and subepithelial white dots
 Refractile lines, or “lattice lines,” best seen
on retroillumination
 Diffuse anterior stromal haze
 Clear peripheral cornea

 Classic lattice dystrophy
 Chromosome 5q31 (Keratoepithelin gene)
 Onset at end of first decade with recurrent
erosions preceding stromal changes
 Corneal sensation is reduced
 Treatment:
 Soft contact lenses to prevent recurrent erosions
 PK or DLK usually needed by sixth decade
 Recurrence in graft is common

 Histology shows amyloid
staining with Congo red
 Green birefringence with
polarized light
 Glassy dots in ant. Stroma
 Fine lattice lines seen on
retroillumination
 Prominent lattice lines and
stromal haze
 Periphery is spared.

 Associated with systemic
amyloidosis
 Chromosome 9q34
 Onset third decade with recurrent
erosions
 more delicate, sparse, radially
oriented lattice lines, which are
more peripherally & spread
centripetally from limbus.
 Increased risk of Glaucoma
 Central cornea spared & corneal
sensations are reduced
 Treatment: same as type I
Extraocularly, amyloid is detected in arterial walls, peripheral nerves, and glomeruli.

 Systemic features:
progressive cranial and peripheral neuropathy
Dysarthia
Dry and lax itchy skin,
Protruding lips
Pendulous ears
Lagophthalmos
• Bilateral facial palsy may be seen mask-like facies

 Type III is AR, IIIa is AD
 Chromosome 5q31
 Onset between fourth and
sixth decade
 Thick, ropy lines with
minimal intervening haze.
 No spontaneous corneal
erosions
 Rapid progression if
subjected to trauma
 Treatment : PK or DLK

 AD
 chromosome 5q31-keratoepithelin gene
 Hyaline deposits that stain red with Masson trichrome stain
 Histochemically, the deposits are noncollagenous protein that
may be derived from the corneal epithelium and/or keratocytes.

 Seen as sharply demarcated irregular
deposits resembling crumbs or snowflakes
in the central anterior stroma, often
distributed in a radial fashion.
 The lesions do not extend to the limbus but
can extend anteriorly through focal breaks in
Bowman layer.
 Patients complain of glare and photophobia.
 Recurrent erosions may occur and vision
decreases as the opacities become more
confluent.
 sensation becomes impaired

 Histology shows amorphous
hyaline
deposits that stain red
with Mason trichrome
 Treatment: PK or DALK by
age 40-50
 Superficial recurrences
treated with excimer laser
keratectomy

 AKA granular-lattice dystrophy
 Older patients have stromal haze between
deposits leading to reduced VA
 Both hyaline deposits typical of granular
dystrophy and amyloid deposits
characteristic of lattice dystrophy
 These extend from the basal epithelium to
the deep stroma.
 Stellate, snowflake-like opacities appear
between the superficial and mid stroma.

Management :
 PTK, LK, or PK may be useful, depending on the depth of the
deposits.
 LASIK and LASEK may result in increased opacification and
are contraindicated.

 Least common dystrophy
 Autosomal recessive
(chromosome 6)
 Systemic inborn error of keratan
sulphate metabolism seems to
have only corneal manifestations
 Multiple, gray-white opacities
that are present in the corneal
stroma and extend into the
peripheral cornea
 Stromal opacities are distributed
throughout the cornea without
clear spaces.

 Symptoms- progressive loss of
vision, pain, photophobia
 Histology- glycosaminoglycan
deposits within stromal
keratocytes
 Treatment
Lamellar/penetrating
keratoplasty

 Rare, slowly progressive
 AD, chromosome 1p36
 Onset as early as first year
of life, but diagnosis
usually not made until
second or third decade
 Local disorder of corneal
lipid metabolism
 Associated with increased
serum cholesterol in 50%
of patients

 Central oval subepithelial opacities (unesterified and
esterified cholesterol)
 Central corneal opacification
 Dense corneal arcus lipoides
 Decreased corneal sensation
 Management: Check lipid profile, PK, PTK for
subepithelial crystals
 Recurrence can occur after PK

 Primary familial amyloidosis
 Uncommon
 AR, Chromosone 1p
 Onset first decade
 Subepithelial and ant stromal amyloid deposition
 Severe photophobia, tearing, visual impairment

 Gradual confluence giving rise to
protruding,mulberry-like
appearance
 Treatment:
 superficial keratectomy or PK
 VERY high recurrence rate in
graft

 AD
 Very slowly progressive
 Unknown cause, possibly due to
deposition of
mucopolysaccharide and lipid
 Opacities densest centrally
 Multiple nebulous, polygonal
gray areas separated by gray
crack-like clear zones
 Theses opacities are densest
centrally and posteriorly and
fade both anteriorly and
peripherally.
Management: none needed as
vision is usually not reduced

Macular Corneal Dystrophy
Granular Corneal Dystrophy
Lattice Corneal Dystrophy

Characteristics Granular Macular Lattice
Inheritance AD AR AD
Age of onset of
symptom
3rd decade 1st decade 1st decade
Epithelial
erosions
Mild Mild – Moderate Severe
Nature of deposit Hyaline GAG Amyloid
Corneal deposits Small discrete ,
clear zone in
between, never
reaches limbus
Irregular
margins, no clear
zones, reaches
limbus
Refractile lines &
dots with central
haze, may
involve limbus

Characteristics Granular Macular Lattice
Opacities Grayish opaque
granules, ‘Bread-
crumbs’ sharp
borders
Grayish opaque
spots, indistinct
borders
Grayish ‘pipe
cleaner’ linear
branching threads
Histochemistry Masson : brilliant
red
Alcian blue : +
Colloidal iron:+
Masson : red
purple
Congo red: +
PAS: +,
Thioflavin- T fluro
: +
Defect Hyaline
degeneration of
collagen
Defective
mucopolysccharid
e metabolism
Primary
amyloidosis of
cornea

 Very common
 May be AD but majority are sporadic
 Female preponderance
 Onset after age 50
 Ranges from asymptomatic guttata to a decompensated cornea
with stromal edema, subepithelial fibrosis, and epithelial bullae

 Pathogenesis Abnormal production of collagenous material by
the affected endothelial cells causes marked thickening of
descemet’s membraneguttae
 Increased corneal edema and deposition of collagen and
extracellular matrix in Descemet’s membrane
 reduction in Na, K-ATPase pump sites and/or function

Hypothesis
 Abnormal final differentiation of neural crest cells – mutation
in collagen producing gene COL8A2
 Increased incidence in female – role of hormone in
pathogenesis
 Alteration in the composition of aqueous humour
 Mitochondrial abnormalities – endothelial Na-K pump requires
tremendous energy which is gained from mitochondria

 Stage 1: asymptomatic, central corneal guttae with fine
pigment dusting, vision and corneal thickness normal
 Stage 2: stromal edema, painless decreased vision(esp upon
awakening),glare and haloes,
specular microscopy – pleomorphism & polymegathism,
increased corneal thickness on pachymetry
 Stage 3: Persistent epithelial edema leading to microcysts and
bullae which cause pain upon rupture
 Stage 4 – growth of avascular subepithelial connective tissue,
scarring, pain diminished but severely reduced vision

(A)Histology of cornea guttata
shows irregular excrescences
of Descemet membrane – PAS
stain;
(B)cornea guttata seen on specular
reflection;
(C) ‘beaten-bronze’ endothelium;
(D) bullous keratopathy;
(E) histology shows severe
epithelial oedema with surface
bullae – PAS stain

 Check pachymetry and specular microscopy (cell count)
 Treatment:
– Reduce edema with NaCl 5% drops
– Lower IOP
– BCL to protect exposed nerve endings
– PK- high success rate, or DSEK

 Autosomal dominant
 Onset – 2nd-3rd decade(congenital variant
manifests at birth)
 Clinical features
 vesicular lesions, band lesions, diffuse
opacities on descemet’s membrane
 Corneal edema, irido corneal adhesions,
corectopia, glaucoma

 Histology – epithelialisation of endothelium ,
metaplasia of endothelial cells into fibroblast,
pleomorphism and degeneration of endothelial cells,
thickening of descemet’s membrane
 Treatment – penetrating keratoplasty

 Rare dystrophy in which there is focal or generalized
absence of corneal endothelium
 AD on 20p11 or AR on 20p13
 Onset is perinatal
 Cornea may range from blue-gray with ground glass
appearance to total opacification and thus variable visual
impairment
 Two forms CHED 1 & 2

CHED 1 CHED 2
Autosomal dominant
(chr 20)
Autosomal recessive
Clear cornea at birth Corneal clouding at birth
Photophobia and epiphora
common
No Photophobia and epiphora
Vision better Vision poor
Nystagmus uncommon Nystagmus common

 Histology – deposition of
abnormal collagen layer
containing disorganised
collagen fibrils with
interspersed basement
membrane like material
 Treatment – penetrating
keratoplasty

 EBMD
 Meesmann epithelial dystrophy
 Reis Buckler dystrophy
 Schnyder central crystalline dystrophy
 Lattice dystrophy
 Granular corneal dystrophy type I

 EBMD
 Reis Bucklers Dystrophy
 Thiel Behnke Dystrophy
 Lattice Corneal Dystrophy type I
UNCOMMON
 Lattice corneal dystrophy type II
 Granular corneal dystrophy type I and II

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